Interactions between platelet activating factor and eicosanoids during endotoxic shock in anaesthetized pigs

The effects of platelet activating factor (PAF) on eicosanoid release during endotoxic shock was investigated in anaesthetized pigs receiving 5 mug kg(-1) Escherichia coli endotoxin (LPS) into the superior mesenteric artery over a 60 min period, by measuring plasma levels of a variety of mediators. Fifteen of the 31 animals infused with LPS and not treated with BN 52021, a PAF receptor antagonist, died within 30 min after the commencement of LPS infusion (non-survivors), while the other 16 survived the experimental period of 3 h, though in a state of shock (survivors). No alterations were observed in plasma concentrations of eicosanoids in the non-survivors. A significant, though transient, increase in eicosanoid concentrations occurred only in the survivors. Treatment with BN 52021 (4 mg kg-1, i.v.) injected 5 min prior to LPS infusion, failed to exert any effect on the survival rate. However, pretreatment with BN 52021 prevented circulatory collapse in the survivors and reduced the concentration of cyclooxygenase enzyme products, without affecting LTB(4) release. Exogenous administration of PAF (0.01 mug kg(-1)) caused hypotension and increased TXB(2) levels although 6-keto PGF(1alpha) and LTB(4) concentrations were unchanged. The data suggest that prostanoid formation may be secondary to PAF release in circulatory collapse evoked by LPS infusion in survivors, and give further support to the suggestion that PAF prostanoid interaction is important during endotoxic shock. However, their role in early death seems to be negligible, indicating the importance of other mediators.     

High Density Lipoprotein Protects against Polymicrobe-induced Sepsis in Mice

HDL has been considered to be a protective factor in sepsis; however, most contributing studies were conducted using the endotoxic animal model, and evidence from clinically relevant septic animal models remains limited and controversial. Furthermore, little is known about the roles of HDL in sepsis other than LPS neutralization. In this study, we employed cecal ligation and puncture (CLP), a clinically relevant septic animal model, and utilized apoA-I knock-out (KO) and transgenic mice to elucidate the roles of HDL in sepsis. ApoA-I-KO mice were more susceptible to CLP-induced septic death as shown by the 47.1% survival of apoA-I-KO mice versus the 76.7% survival of C57BL/6J (B6) mice (p = 0.038). ApoA-I-KO mice had exacerbated inflammatory cytokine production during sepsis compared with B6 mice. Further study indicated that serum from apoA-I-KO mice displayed less capacity for LPS neutralization compared with serum from B6 mice. In addition, apoA-I-KO mice had less LPS clearance, reduced corticosterone generation, and impaired leukocyte recruitment in sepsis. In contrast to apoA-I-KO mice, apoA-I transgenic mice were moderately resistant to CLP-induced septic death compared with B6 mice. In conclusion, our findings reveal multiple protective roles of HDL in CLP-induced sepsis. In addition to its well established role in neutralization of LPS, HDL exerts its protection against sepsis through promoting LPS clearance and modulating corticosterone production and leukocyte recruitment. Our study supports efforts to raise HDL levels as a therapeutic approach for sepsis.     

Increased Production of Interleukin-10 and Tumor Necrosis Factor-Alpha in Stimulated Peripheral Blood Mononuclear Cells after Inhibition of S100A12

Sepsis may induce immunosuppression and result in death. S100A12 can bind to the receptor for advanced glycation end-products (RAGE) and Toll-like receptor (TLR)4 following induction of various inflammatory responses. It is unclear whether S100A12 significantly influences the immune system, which may be associated with sepsis-related mortality. We measured plasma S100A12 levels and cytokine responses (mean ± standard error mean) of lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs) after S100A12 inhibition in healthy controls and patients with sepsis on days one and seven. Day one plasma soluble RAGE (sRAGE) and S100A12 levels in patients with sepsis were significantly higher than those in controls (2481.3 ± 295.0 vs. 1273.0 ± 108.2 pg/mL, p < 0.001; 530.3 ± 18.2 vs. 310.1 ± 28.1 pg/mL, p < 0.001, respectively). Day seven plasma S100A12 levels in non-survivors were significantly higher than those in survivors (593.1 ± 12.7 vs. 499.3 ± 23.8 pg/mL, p = 0.002, respectively). In survivors, plasma sRAGE levels were significantly decreased after 6 days (2297.3 ± 320.3 vs. 1530.1 ± 219.1 pg/mL, p = 0.009, respectively), but not in non-survivors. Inhibiting S100A12 increased the production of tumor necrosis factor (TNF)-α and interleukin (IL)-10 in stimulated PBMCs for both controls and patients. Therefore, S100A12 plays an important role in sepsis pathogenesis. S100A12 may competitively bind to TLR4 and RAGE, resulting in decreased IL-10 and TNF-α production.     

对脆弱类杆菌β-内酰胺酶及其与肠道微生态学关系的初步探讨

本文利用β-内酰胺酶作为分类学研究的方法,探讨了脆弱类杆菌与肠道菌之间的微生态学关系。临床分离菌株脆弱类杆菌55的β-内酰胺酶经离子交换层析、凝胶过滤和制备型聚丙烯酰胺凝胶电泳进行纯化,纯酶与脂质体-CPS-K佐剂混合制备抗血清,并建立IgG-ELISA和Western blotting方法,其测定结果均表明脆弱类杆菌的β-内酰胺酶不同于其它类杆菌和肠道菌的β-内酰胺酶,具有种的特异性。     

Sequential release of eicosanoids during endotoxin-induced shock in anesthetized pigs

The release of eicosanoids during endotoxin shock was investigated in anesthetized pigs receiving 5 micrograms/kg Escherichia coli lipopolysaccharide (LPS) over 60 min into the superior mesenteric artery. TXB2, 6-keto PGF1 alpha and LTB4 concentrations in blood obtained from the superior mesenteric vein (SMV), right ventricle (RV) and aorta, during LPS infusion and an additional period of 2 h, were assessed along with hemodynamic variables, blood gases and pH and laboratory parameters. Half of the animals died within 30 min after termination of LPS infusion (non-survivors, n = 8), while the other half survived the experimental period of 3 h, though in a shock state (survivors, n = 9). The non-surviving pigs demonstrated progressively reduced cardiac output, hypotension and hypoperfusion in all organs. The surviving pigs demonstrated also a reduced cardiac output, which however was compensated by an elevated systemic vascular resistance resulting in a maintenance of arterial blood pressure. After exhausting this compensation the flow to non-vital organs increased and consequently arterial blood pressure was reduced resulting in hypoperfusion. In survivors a marked, though, transient increase was measured in concentrations of TXB2 and 6-keto PGF1 alpha level. A significant increase was measured in plasma concentration of LTB4 in SMV without any elevation in RV and aorta. LTB4 production started when prostanoid release had decreased. In contrast to survivors, no changes could be observed in eicosanoid release for non-survivors. A correlation was observed between systemic vascular resistance and TXB2 to 6-keto PGF1 alpha ratio.(ABSTRACT TRUNCATED AT 250 WORDS)     

Normalization of the increased translocation of endotoxin from gram negative enterobacteria (leaky gut) is accompanied by a remission of chronic fatigue syndrome

There is now evidence that chronic fatigue syndrome (CFS) is accompanied by an increased translocation of endotoxins from gram-negative enterobacteria through the gut wall, as demonstrated by increased prevalences and median values for serum IgM and IgA against the endotoxins of gram-negative enterobacteria. This condition can also be described as increased gut permeability or leaky gut and indicates intestinal mucosal dysfunction (IMD). Here we report a case of a 13 year old girl with CFS who showed very high values for serum IgM against the LPS of some enterobacteria and signs of oxidative and nitrosative stress, activation of the inflammatory response system, and IgG3 subclass deficiency. Upon treatment with specific antioxidants and a "leaky gut diet", which both aim to treat increased gut permeability, and immunoglobins intravenously, the increased translocation of the LPS of gram negative enterobacteria normalized and this normalization was accompanied by a complete remission of the CFS symptoms.     

Identification of Bacteroides fragilis by co-agglutination, using a specific monoclonal antibody

A monoclonal antibody, mAbC3 (IgG(2b)), specific for the Bacteroides fragilis lipopolysaccharide (LPS) was produced and found to react with a common epitope in most strains within the species. mAbC3 was adsorbed to Staphylococcus aureus Cowan I strain and used in a co-agglutination assay for identification of B. fragilis. Almost 98% of the B. fragilis strains were positive in co-agglutination. Among the 283 non-B. fragilis only two strains showed false positive reaction. These results show that the mAbC3 has a high specificity and can be used for the rapid identification of the B. fragilis species.     

Biological activity of lipopolysaccharides from clinical Bacteroides fragilis strains isolated in Poland determined in reaction with limulus amoebocyte lysate

The aim of this study was to determine a biological activity of lipopolysaccharides (LPS) from clinical Bacterioides fragilis strains isolated in Poland by means of quantitative, photometric BET (LAL) method with Limulus polyphemus amoebocyte lysate and chromogenic substrate S-2423. Lipopolysaccharides were extracted from nine clinical B. fragilis strains by the procedure of Westphal and Jann (1965). Crude LPS preparations were purified with ultracentrifugation. Biological activities of bacterial endotoxins were determined by quantitative BET method with chromogenic substrate S-2423 (ENDOCHROME kit). Tests were performed according to the recommendations of the producer (Charles River Endosafe Ltd., USA). E. coli O55:B5 LPS and LPS preparations from reference B. fragilis strains were applied to compare the results of examinations. Activities of endotoxins from clinical B. fragilis strains isolated in Poland determined in reaction with Limulus amoebocyte lysate were differentiated. Among endotoxins of clinical B. fragilis strains the most active was the preparation from strain cultured in the case of pancreatic ulcer (B. fragilis 80/81 LPS). Lipopolysaccharides of examined B. fragilis strains were less active in BET test than E. coli O55:B5 LPS.     

Adhesion of human granulocytes and T lymphocytes to vascular endothelial cells after stimulation with Bacteroides fragilis endotoxin and enterotoxin]

The aim of presented study was to estimates the number of human granulocytes and T lymphocytes adhering to 1 mm2 of vascular endothelial cell culture stimulated by Bacteroides fragilis endotoxins (LPS) and enterotoxin (BFT). HMEC-1 cells were activated with bacterial preparations at the concentration of 10 (micrograms/ml for 4 and 24 hours. Granulocytes and T lymphocytes were isolated from peripheral blood of healthy blood donors. The adhesion tests of granulocytes and adhesion tests of resting and activated with PMA (at the concentration of 10 ng/ml) T lymphocytes to the non-stimulated and stimulated by B. fragilis compounds (LPS and BFT) vascular endothelium were performed. The number of viable leukocytes, which adhered to the endothelium, was determined using inverted microscope (magnification 200x). The results were presented as the number of viable cells adhering to 1 mm2 of the endothelial cell culture. The results of experiments indicate that granulocytes and T lymphocytes (resting and after activation with PMA even in greater number) adhere to the endothelial cells stimulated by B. fragilis endotoxins and enterotoxin. B. fragilis toxins are weaker stimulants of human leukocyte adhesion to the HMEC-1 cells than E. coli O55:B5 LPS. B. fragilis LPS and BFT preparations stimulate endothelial cells to the adhesion of granulocytes in similar manner, whereas the activation of vascular endothelium to the adhesion of T lymphocytes is differentiated.     

Sequential measurement of IL-6 blood levels in patients with systemic inflammatory response syndrome (SIRS)/sepsis

This study was undertaken to investigate whether sequential measurement of blood interleukin (IL)-6 levels using chemiluminescent enzyme immunoassay (CLEIA) would be useful for the management of patients with systemic inflammatory response syndrome (SIRS)/sepsis. Forty consecutive patients with SIRS/sepsis admitted to ICU were involved in the study. Blood IL-6 level was measured everyday throughout their ICU stay at the clinical laboratory by CLEIA method. The platelet count and the sequential organ failure assessment (SOFA) score were measured consecutively. The blood IL-6 levels were elevated in SIRS/sepsis patients and were extremely high in patients with septic shock. There was no significant difference in the blood IL-6 level on admission between survivors (n=27) and non-survivors (n=13). However, the mean blood IL-6 level during ICU stay was significantly higher in the non-survivors (p<0.05). There were significant correlation between the peak IL-6 blood level and the lowest platelet count, and between the peak IL-6 blood level and the maximum SOFA score, respectively. The platelet count became lowest 2.0+/-2.0 days later on average, and the SOFA score became maximal 2.5+/-1.4 days later on average following the day when IL-6 reached its peak value. Sequential measurement of blood IL-6 levels by CLEIA is useful in evaluating the severity and in predicting the outcome of the patients with SIRS/sepsis.     

Identification of Bacteroides fragilisby a modified immuno polymerase chain reaction (mIPCR), using a specific monoclonal antibody

Bacteroides fragilis is the anaerobic species most commonly isolated from human clinical specimens, and is resistant to many antimicrobial agents. A monoclonal antibody, mAb4H8 (IgG3), reacting with a specific epitope in the lipopolysaccharide (LPS) isolated from most of the B. fragilis strains, was produced and employed with modified Immuno Polymerase Chain Reaction (mIPCR) for identification of B. fragilis with a detection limit of 10(4) cfu/mL bacterial suspension. A number of bacterial strains were examined, including B. fragilis, Bacteroides spp. other than B. fragilis and other genera. All the B. fragilis strains with the immunodominant (beta1,6-linked D-galactosyl chain) epitope were positive. None of the other strains showed the positive reaction. The results indicate that mIPCR assay with mAb4H8 has a high specificity and high sensitivity.     

Human endothelial cell adhesiveness for neutrophils, induced by Escherichia coli lipopolysaccharide in vitro, is inhibited by Bacteroides fragilis lipopolysaccharide

Recent studies in vitro have demonstrated that LPS from Gram-negative bacteria are capable of inducing endothelial cells to express a cell surface property that promotes the adherence of neutrophils (polymorphonuclear cells, PMN). We have investigated the effects of LPS from Bacteroides fragilis, an organism documented to have little toxicity in vivo, on the induction of this property in human endothelial cells. Monolayers of cultured human umbilical vein endothelial cells (HUVE) exhibited no increase in adhesiveness for 51Cr-radiolabeled PMN after 4 h of exposure to B. fragilis LPS from 1 ng to 10 micrograms/ml. Escherichia coli LPS elicited a dose-dependent enhancement of HUVE adhesiveness for PMN over the same concentration range, reaching a maximum of 49.4 +/- 6.6% at 10 micrograms/ml. Like E. coli LPS, B. fragilis LPS converted chromogenic substrate in the Limulus amebocyte lysate assay, and was directly cytotoxic to bovine aortic endothelial cells. Both B. fragilis LPS activities required doses two-to-three log-fold higher than for E. coli LPS. In addition, we found that B. fragilis LPS inhibited the induction of HUVE adhesiveness for PMN by E. coli LPS. This inhibition was also dose-dependent, becoming maximal (greater than 80%) when B. fragilis LPS was in 10- to 20-fold excess. Tumor necrosis factor and IL-1, two monokines which also elicit HUVE adhesiveness for PMN, were not inhibited by B. fragilis LPS, suggesting a mechanism of HUVE activation by LPS which is signal-specific, and which recognizes specificities of LPS structure.     

Serum IgG response to Burkholderia cepacia outer membrane antigens in cystic fibrosis: Assessment of cross-reactivity with Pseudomonas aeruginosa

Abstract Burkholderia cepacia (Pseudomonas cepacia) is now recognised as an important pathogen in cystic fibrosis patients, and several reports have suggested that sputum-culture-proven colonisation occurs despite the presence of specific antibody. In an attempt to establish the use of antibody studies as diagnostic and prognostic indicators of B. cepacia infection, we have examined the IgG response to B. cepacia outer membrane proteins and lipopolysaccharide in patients also colonised with P. aeruginosa . The B. cepacia strains were grown in a modified iron-depleted chemically defined medium and outer membrane components examined by SDS-PAGE and immunoblotting. IgG antibodies were detected against B. cepacia outer membrane antigens, which were not diminished by extensive preadsorption with P. aeruginosa . The response to B. cepacia O-antigen could be readily removed by adsorption of serum either with B. cepacia whole cells or purified LPS, whereas we were unable to adsorb anti-outer membrane protein antibodies using B. cepacia whole cells. The inability to adsorb anti-outer membrane protein antibodies using B. cepacia whole cells maybe due to non-exposed surface epitopes. Several B. cepacia sputum-culture negative patients colonised with P. aeruginosa had antibodies directed against B. cepacia outer membrane protein. This study suggests that there is a specific anti- B. cepacia LPS IgG response, which is not due to antibodies cross-reactive with P. aeruginosa . Our studies indicate that much of the B. cepacia anti-outer membrane protein response is specific and not attributable to reactivity against co-migrating LPS.     

Feasibility of prophylaxis and therapy against Gram-negative infections by human monoclonal antibodies

Abstract In a murine model of Gram-negative sepsis, we have shown that the prophylactic application of human monoclonal antibodies (HmAbs) with specificity for lipopolysaccharides (LPS) of Pseudomonas aeruginosa protected against bacterial infection. In this paper we show that the therapeutical application of 5 μg of these HmAbs up to 6 h after challenge with a lethal dose of live P. aeruginosa results in a protection rate of 70–90%. Administration 18 h after bacterial challenge, diminished the protection to 43% survival rate. Furthermore, using a mixture of HmAbs recognizing a total of six different P. aeruginosa serotypes, no interference in their protective capacities was found. Finally, these HmAbs also protected galactosamine-sensitized mice against lethal challenge with LPS. Our data show that the described HmAbs confer bactericidal activity as well as anti-endotoxic activity in vivo.     

Clinical Importance of Infections due to Bacteroides fragilis and Role of Antibiotic Therapy

Out of 200 infections due to Bacteroides fragilis occurring over a period of three years 133 were related to the intestinal tract, 55 to the genitourinary tract, and the remainder were in bedsores and ulcers; 56% occurred in patients undergoing major intestinal surgery.B. fragilis was isolated in pure culture from 56% of the infections. In mixed culture it was most commonly associated with Klebsiella and Enterobacter species. Other anaerobic bacteria were isolated in 9% of the mixed cultures.Altogether 131 (65·5%) of the patients recovered without antibiotic therapy or further surgery, but 59 (29·5%) developed complications and 10 (5%) died. The commonest complication was abscess formation, and the incidence was highest with infections associated with malignancy (44%) and lowest with obstetric infections (5%). The mortality was 5% overall but in the presence of bacteraemia it rose to 33%.Only 43 patients received appropriate chemotherapy. Clindamycin was the most effective antibiotic, having a recovery rate of 78%, but this rate was little better than in untreated patients (65%). The role of prophylactic antibiotic therapy in preventing bacteroides infection remains to be studied.The incidence of the isolation of bacteroides from wound infections after major intestinal surgery rose from 13% in 1970 to 81% in 1973. This increase was due to both the accurate collection and care of specimens while in transit to the laboratory and the use of selective media for the isolation of bacteroides in laboratory culture. The importance of these precautions is emphasized.     

IgG1 and IgG2a production by autoimmune B cells treated in vitro with IL-4 and IFN-gamma

Autoimmune MRL-lpr/lpr and NZB/W mice spontaneously secrete large quantities of pathogenic IgG1 and IgG2a autoantibodies. NZB mice also produce autoantibodies but these tend to be of the IgM H chain class. This work examines whether differences in the isotype of autoantibody produced by lupus-prone mice reflects differences in the sensitivity of autoreactive B cells to lymphokine-mediated IgG secretion. Twenty-five percent of normal BALB/c B cells produced IgG1 when stimulated in vitro with IL-4 plus LPS. This was comparable with the effect of IL-4 on small resting B cells from MRL-lpr/lpr and NZB/W mice. In contrast, less than 8% of the resting B cells from NZB mice produced IgG1 under these conditions. LPS plus IFN-gamma induced 5% of BALB/c and NZB/W but only 1% of NZB B cells to secrete IgG2a. Because lymphocytes from both young and old NZB mice showed diminished IgG1 and IgG2a secretion after lymphokine treatment, B cells from this strain appeared to be intrinsically resistant to the effects of IL-4 and IFN-gamma. In contrast, a disproportionately large proportion (22%) of B cells from adult MRL-lpr/lpr mice produced IgG2a when treated with IFN-gamma in vitro. Only B cells from MRL-lpr/lpr mice with active disease responded with such high levels of IgG2a production: cells from animals that had not yet developed clinical disease produced normal levels of IgG2a. Within each strain, B cells producing antibodies against autoantigens such as DNA, bromelain-treated mouse RBC and Sm responded to treatment with IL-4 and IFN-gamma in a manner indistinguishable from B cells producing antibodies against conventional Ag such as TNP and ARS.     

The role of lipopolysaccharide in stimulating adrenomedullin production during polymicrobial sepsis

Previous studies have shown that adrenomedullin (AM), a potent vasodilatory peptide, is upregulated during sepsis. However, it remains unknown whether the increased AM observed under such conditions is solely due to the elevated levels of circulating lipopolysaccharide (LPS). To determine this, an Alzet micro-osmotic pump, containing a low dose of Escherichia coli LPS or vehicle (sterile normal saline), was implanted in the peritoneal cavity of the normal male adult rat. At 10 h after the pump implantation, samples of blood and small intestine were harvested for the determination of AM by radioimmunoassay. In additional groups, rats were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP). LPS binding agent polymyxin B was administrated intramuscularly at 1 h prior to as well as 5 h after the onset of sepsis. At 10 h after CLP or sham-operation, blood and intestinal samples were harvested and levels of AM were then determined. Plasma levels of LPS were also measured by Limulus amebocyte lysate assay. The results indicate that administration of a low dose of LPS via the peritoneal cavity in normal animals (which did not significantly alter cardiac output, blood pressure or heart rate) markedly increased plasma and intestinal levels of AM. In addition, plasma and tissue levels of AM increased significantly at 10 h after CLP. Administration of polymyxin B, however, attenuated the increase in AM levels under such conditions. Similarly, the increased plasma levels of LPS was significantly reduced by polymyxin B during sepsis. These results, taken together, suggest that the upregulated AM observed during polymicrobial sepsis is at least in part due to the increase in circulating levels of endotoxin.     

非酒精性脂肪性肝炎患者肠道菌群失调与肠道通透性及血清内毒素的相关性研究

目的 探讨非酒精性脂肪性肝炎患者肠道菌群失调与肠道通透性及血清内毒素的相关性.方法 选择肠道菌群中具有代表性的细菌共8种进行培养.研究对象为健康成人(A组)和非酒精性脂肪性肝炎(B组)各30例,计数两组肠道菌群中8种细菌的数量,检测所有被研究者的血清内毒素、二胺氧化酶(DAO)、D-乳酸及TNF-α的浓度,比较两组细菌数量和血清指标的变化,并进行相关分析.结果 与A组比较,B组双歧杆菌、乳杆菌和拟杆菌的菌落数显著减少(P＜0.01或P＜0.05),而肠球菌、肠杆菌的菌落数则有显著增加(P＜0.01或P＜0.05);酵母真菌、葡萄球菌、梭菌菌落数没有发生显著改变(P＞0.05);血清内毒素、DAO、D-乳酸、TNF-α水平显著增高(P＜0.01);相关分析显示肠杆菌与内毒素、DAO、D-乳酸相关(r=0.644,P＜0.001;r=0.415,P=0.023;r =0.383,P=0.037);血清内毒素和DAO、D-乳酸、TNF-α显著相关(r=0.485,P=0.007;r=0.477,P=0.008;r=0.490,P=0.006);TNF-α则与DAO、D-乳酸相关(r=0.426,P =0.019;r =0.440,P=0.015).结论 非酒精性脂肪性肝炎患者存在肠道菌群失调、肠道通透性增高及肠源性内毒素血症,肠杆菌的过度生长与肠源性内毒素血症及肠道通透性密切相关.     

Toxins of Bacteroides fragilis and Bacteroides thetaiotaomicron rods as stimulators of adhesion molecule expression on the surface of vascular endothelial cells

Lipopolysaccharides from four Bacteroides fragilis strains: one nonenterotoxigenic (NTBF) and three enterotoxigenic (ETBF), and from three B. thetaiotaomicron strains were extracted by hot phenol-water method and purified. B. fragilis enterotoxin was prepared according to the procedure of van Tassell et al. (1992). The influence of the examined toxins on the expression of adhesion molecules: ICAM-1, VCAM-1 and E-selectin on HMEC-1 (human dermal microvascular endothelial cells) was assayed in ELISA test with monoclonal antibodies. Four concentrations of toxins were applied: 0.01, 0.1, 1.0 and 10.0 (micrograms/ml). Endothelial cells were activated for 24 hours (ICAM-1 and VCAM-1 expression) and for 4 hours (E-selectin expression). The coloured product of immunoenzymatic reaction was measured by reading the absorbance at wavelength 492 nm. Two controls were performed in each experiment: with resting HMEC-1 and E. coli O55:B5 LPS (Sigma, USA). Bacteroides fragilis and B. thetaiotaomicron lipopolysaccharides stimulated three adhesion molecules under investigation. Their activity was comparable, but weaker than the activity of E. coli O55:B5 LPS. ICAM-1 was the most stimulated molecule. B. fragilis enterotoxin induced two adhesion molecules: VCAM-1 and E-selectin demonstrating weaker stimulatory activity than E. coli LPS. Stimulation of adhesion molecules on vascular endothelial cells should be considered to be a biological activity of B. fragilis and B. thetaiotaomicron endotoxins and B. fragilis enterotoxin.